I have read many posts about guaifenisin, and frankly all the talk about herxing was scaring me off from trying it. I didn't want anything making me feel worse than I already am. I visited my primary doc's partner recently who suggested that I try it. He prescribed 1200mg twice a day with plenty of water. Since taking it I have an increase in generalized muscle pain, and more headaches which seem to be caused by muscle spasms in my neck. Are these symptoms to expect when first starting gaui? What symptoms shoud I expect when first starting? How long of a trail period should I use? The doc said give it a month. Any words of advice would be appreciated. I know I could do a search on guai, but it will take a long time to weed through it all. Thanks. Also, it was interesting to note that neither the doctor or the pharmacist said anything about avoiding aspirin while taking this. Occasionaly I take one Excedrin for the bad headaches. This contains aspirin. If I continue to do that, how much does it negate the effects of the guai?